<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
    <style>
            .login-header {
              width: 100%;
              text-align: center;
              height: 30px;
              font-size: 24px;
              line-height: 30px;
            }
        
            ul, li, ol, dl, dt, dd, div, p, span, h1, h2, h3, h4, h5, h6, a {
              padding: 0px;
              margin: 0px;
            }
        
            .login {
              width: 512px;
              position: absolute;
              border: #ebebeb solid 1px;
              height: 280px;
              left: 50%;
              right: 50%;
              background: #ffffff;
              box-shadow: 0px 0px 20px #ddd;
              z-index: 9999;
              margin-left: -250px;
              margin-top: 140px;
              display: none;
            }
        
            .login-title {
              width: 100%;
              margin: 10px 0px 0px 0px;
              text-align: center;
              line-height: 40px;
              height: 40px;
              font-size: 18px;
              position: relative;
              cursor: move;
              -moz-user-select: none; /*火狐*/
              -webkit-user-select: none; /*webkit浏览器*/
              -ms-user-select: none; /*IE10*/
              -khtml-user-select: none; /*早期浏览器*/
              user-select: none;
            }
        
            .login-input-content {
              margin-top: 20px;
            }
        
            .login-button {
              width: 50%;
              margin: 30px auto 0px auto;
              line-height: 40px;
              font-size: 14px;
              border: #ebebeb 1px solid;
              text-align: center;
            }
        
            .login-bg {
              width: 100%;
              height: 100%;
              position: fixed;
              top: 0px;
              left: 0px;
              background: #000000;
              filter: alpha(opacity=30);
              -moz-opacity: 0.3;
              -khtml-opacity: 0.3;
              opacity: 0.3;
              display: none;
            }
        
            a {
              text-decoration: none;
              color: #000000;
            }
        
            .login-button a {
              display: block;
            }
        
            .login-input input.list-input {
              float: left;
              line-height: 35px;
              height: 35px;
              width: 350px;
              border: #ebebeb 1px solid;
              text-indent: 5px;
            }
        
            .login-input {
              overflow: hidden;
              margin: 0px 0px 20px 0px;
            }
        
            .login-input label {
              float: left;
              width: 90px;
              padding-right: 10px;
              text-align: right;
              line-height: 35px;
              height: 35px;
              font-size: 14px;
            }
        
            .login-title span {
              position: absolute;
              font-size: 12px;
              right: -20px;
              top: -30px;
              background: #ffffff;
              border: #ebebeb solid 1px;
              width: 40px;
              height: 40px;
              border-radius: 20px;
            }
        
        
          </style>
        
</head>
<body>
        <div class="login-header"><a id="link" href="javascript:void(0);">点击，弹出登录框</a></div>
        <div id="login" class="login">
          <div id="title" class="login-title">登录会员
            <span><a id="closeBtn" href="javascript:void(0);" class="close-login">关闭</a></span></div>
          <div class="login-input-content">
            <div class="login-input">
              <label>用户名：</label>
              <input type="text" placeholder="请输入用户名" name="info[username]" id="username" class="list-input">
            </div>
            <div class="login-input">
              <label>登录密码：</label>
              <input type="password" placeholder="请输入登录密码" name="info[password]" id="password" class="list-input">
            </div>
          </div>
          <div id="loginBtn" class="login-button"><a href="javascript:void(0);" id="login-button-submit">登录会员</a></div>
        </div><!--登录框-->
        <div id="bg" class="login-bg"></div><!--遮挡层-->
        
    <script>
        var login = document.getElementById('login');
        document.getElementById('link').onclick=function(){
            login.style.display='block';
            document.getElementById('mask').style.display='block'
        }
        document.getElementById('closeBtn').onclick=function(){
            login.style.display='none';
            document.getElementById('mask').style.display='none'
        }
        document.getElementById('title').onmousedown=function(e){
            //鼠标按下，获取clientX,offsetLeft,差值不变
            var spaceX = e.clientX - login.offsetLeft;
            var spaceY = e.clientY - login.offsetTop;
            document.onmosemove=function(e){
                var x = e.clientX -spaceX;
                var y = e.clientY -spaceY;
                login.style.left =x + 'px';
                login.style.top = y + 'px';
            }
        }
    
    
    </script>
</body>
</html>